In the prior art, the usual rocket motor has folded flatblade fins which extend to the rear of the motor case, with four nozzle assemblies between them. The fins deploy after the rocket exits the launching tube, and are locked in an extended position at an angle of 45 degrees from the rocket axis. The rocket velocity at the exit from the launcher tube is generally insufficient to achieve adequate fin stabilization unless the rocket is fired from a high-velocity aircraft or other vehicle. Motors for rockets intended to be deployed from helicopters or other low velocity vehicles have been made with scarfed nozzles to impart some spin stabilization to such rockets during early flight. Spin velocities of 8 to 11 revolutions per second, achieved by this method, reduce dispresion of the rockets, but the continued application of the torque force after fin deployment produces a yaw motion which is undesirable.
Other prior rocket constructions have attempted to deal with this problem by inserting canted vanes into the rocket nozzle, while constructing the vanes so that they are burned out early in flight. However, difficulties have been encountered due to nonuniformity in the burn-out of the vanes. Moreover, the burn-out of the vanes may produce debris in some cases, which is undesirable because such debris may possibly damage the helicopter.